Formic Acid Acting as an Efficient Oxygen Scavenger in Four-Electron Reduction of Oxygen Catalyzed by a Heterodinuclear Iridium−Ruthenium Complex in Water

A heterodinuclear iridium−ruthenium complex [Ir^III(Cp*)(H₂O)(bpm)Ru^II(bpy)₂](SO₄)₂ (Cp* = η⁵-pentamethyl-cyclopentadienyl, bpm = 2,2′-bipyrimidine, bpy = 2,2′-bipyridine) acts as an effective catalyst for removal of dissolved O₂ by the four-electron reduction of O₂ with formic acid in water at an ambient temperature.